Spout2NDI on DJ setup?

1

I’m running Synesthesia on one computer and OBS on the other. OBS drives the main output to a projector.

I’d like to being Synesthesia visuals into OBS. Have tried the NDI screen capture tool but it’s not usable as the Synesthesia visuals are best synced.

I saw Spout2NDI. Could this be an option or does it use the same underlying NDI transport and hence won’t be usable in a time sensitive environment?

Note: I successfully ran Spout to OBS on the same laptop but can’t run both OBS and Synesthesia on the same machine; the specs don’t allow it

2

If I understand correctly you need to run Synesthesia on one machine and bring it’s output to OBS on another.

Synesthesia has Spout output so you could use Spout to NDI to send to the other machine and receive into OBS on that machine.

3

Yes that’s correct. What I’m not sure is whether the underlying transport is different to NDI Screen capture for Spout2NDI as the screen capture feed has a delay of about 2 secs. Given NDI is used for gaming there should be latencies less then 50ms.

I’m not at my machine so can’t test at the moment

4

I do not find high latency for NDI screen capture but rather hesitations unless set to 60fps. The region of interest function suggests that the whole screen is captured, possibly by DXGI screen duplication which is very efficient. The reason for the hesitation is likely to be something else.

Spout to NDI takes the Spout sender’s texture as input, downloads the pixels from GPU to CPU and sends that buffer to NDI.

The overhead for GPU>CPU download is reduced with the “Texture readback buffering” setting and the NDI sending is optimized by the “YUV format sending” setting. The underlying NDI send function operates as provided for by the NDI SDK.

5

Ok, got this setup. While it’s better it’s still visibly behind in OBS. However the interesting thing is the NDI monitor on the OBS end is almost identical to the Synesthesia source which would eliminate the network (Wifi at the moment) and also confirm the performance of Spout2NDI. I wonder whether I can further fine tune the OBS NDI plugin/OBS setup which may be a question for another forum. At the moment it’s still not usable.

However back to Spout2NDI do you think shrinking the region of interest could improve performance?

6

Reducing the region of interest in the NDI capture application would make a difference by reducing the size of the NDI image. The same would apply to the Spout source for Spout to NDI. My experience is that anything above 1920x1080 has poor performance.

I am not sure how you would fine tune the OBS NDI plugin unless there are user settings you can adjust.

If you can isolate the latency of 2 seconds to NDI screen capture, it’s worth asking on the NDI forum.